/*
 *      ID : pallab81
 *      PROG : 10271
 *      LANG : C++
 *
 *      2012-06-11 12:48:52
 *      "I have not failed, I have just found 10000 ways that won't work.
 */

#include <iostream>
#include <algorithm>
#include <vector>
#include <sstream>
#include <fstream>
#include <string>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <functional>
#include <bitset>
#include <iomanip>

#include <ctime>
#include <cassert>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <climits>
#include <cstdlib>

using namespace std;


#define foR(i1,st,ed) for(int i1 = st , j1 = ed ; i1 < j1 ; ++i1 )
#define fo(i1,ed) foR( i1 , 0 , ed )
#define foE(i1,st,ed) foR( i1, st, ed+1 )
#define foit(i, x) for (typeof((x).begin()) i = (x).begin(); i != (x).end(); i++)
#define bip system("pause")
#define Int long long
#define pb push_back
#define SZ(X) (int)(X).size()
#define LN(X) (int)(X).length()
#define mk make_pair
#define SET( ARRAY , VALUE ) memset( ARRAY , VALUE , sizeof(ARRAY) )
#define line putchar_unlocked('\n')

template<class T1>
inline void debug(T1 _x) {
    cout<<_x<<'\n';
}
template<class T1, class T2>
inline void debug(T1 _x,T2 _y) {
    cout<<_x<<' '<<_y<<'\n';
}
template<class T1, class T2, class T3>
inline void debug(T1 _x,T2 _y,T3 _z) {
    cout<<_x<<' '<<_y<<' '<<_z<<'\n';
}
template<class T1, class T2, class T3, class T4>
inline void debug(T1 _x,T2 _y,T3 _z,T4 _zz) {
    cout<<_x<<' '<<_y<<' '<<_z<<' '<<_zz<<'\n';
}
template< class T1>
inline void debug(T1 _array,int _size) {
    cout<<"[";
    for (int i=0; i<_size; ++i) {
        cout<<' '<<_array[i];
    }
    puts(" ]");
}

#define getchar getchar_unlocked
#define putchar putchar_unlocked

inline void fastRead(int *a) {
    register char c=0;
    while (c<33) c=getchar();
    *a=0;
    while (c>33)
    {
        *a=*a*10+c-'0';
        c=getchar();
    }
}
inline string fastRead() {
    register char c[33];
    gets(c);
    return (string)c;
}
inline bool CI(int &_x) {
    return scanf("%d",&_x)==1;
}
inline bool CI(int &_x, int &_y) {
    return CI(_x)&&CI(_y) ;
}
inline bool CI(int &_x, int &_y, int &_z) {
    return CI(_x)&&CI(_y)&&CI(_z) ;
}
inline bool CI(int &_x, int &_y, int &_z, int &_zz) {
    return CI(_x)&&CI(_y)&&CI(_z)&&CI(_zz) ;
}
inline void wait( double seconds ) {
    double endtime = clock()+( seconds* CLOCKS_PER_SEC );
    while ( clock() < endtime ) {
        ;
    }
}
namespace In {
int nguest;
int nstick; //<=5000
int sticks[5005];
inline void read() {
    fastRead(&nguest);
    fastRead(&nstick);
    nguest+=8;
    fo(i,nstick) {
        fastRead(&sticks[i]);
    }
}
}
const Int inf = 1023456789;
namespace algo {
Int dp[1009][5001];
bool vis[1009][5001];
inline bool ok(int at, int guestLeft) {
    return ( guestLeft*3 + at <= In::nstick );
}
inline Int badness(int a, int b) {
    Int p = a-b;
    return p*p;
}

Int go(int at, int guestLeft) {
    if (guestLeft==0) {
        return 0;
    }
    if ( vis[guestLeft][at])return dp[guestLeft][at];
    vis[guestLeft][at]=true;
    Int ret=inf;
    if (ok(at,guestLeft)==false) {
        return dp[guestLeft][at]=ret;
    }

    //current chopstick consider na kore
    Int a = go(at+1,guestLeft);
    ret=min(ret,a);

    //current chopstick consider kore
    Int b = badness(In::sticks[at],In::sticks[at+1])+go(at+2,guestLeft-1);
    ret=min(ret,b);

    return dp[guestLeft][at]=ret;
}
inline void Run() {
    SET(vis,false);
    Int res = go(0,In::nguest);
    cout<<res;
    line;
}

}


inline void Solve() {
    In::read();
    //debug(In::nguest,In::nstick,"");
    algo::Run();
}
//#define showcase
int main() {
    int tt;
    CI(tt);
    foE(i,1,tt) {
        Solve();
    }


    return 0;
}

// kate: indent-mode cstyle; space-indent on; indent-width 0; 
